package com.lagou.edu.factory;

import com.lagou.edu.annotation.Autowired;
import com.lagou.edu.annotation.Service;
import com.lagou.edu.annotation.Transactional;
import com.lagou.edu.utils.TransactionManager;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
 * 代理对象工厂：生成代理对象的
 */
@Service
public class ProxyFactory {

    @Autowired
    private TransactionManager transactionManager;

    public void setTransactionManager(TransactionManager transactionManager) {
        this.transactionManager = transactionManager;
    }

    /**
     * Jdk动态代理
     * @param obj 委托对象
     * @return 代理对象
     */
    public Object getJdkProxy(Object obj) {
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(),
                new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        Transactional transactional = method.getAnnotation(Transactional.class);
                        if (transactional == null) {
                            return method.invoke(obj, args);
                        }
                        Object result = null;
                        try{
                            // 开启事务(关闭事务的自动提交)
                            transactionManager.beginTransaction();
                            result = method.invoke(obj, args);
                            // 提交事务
                            transactionManager.commit();
                        }catch (Exception e) {
                            e.printStackTrace();
                            // 回滚事务
                            transactionManager.rollback();
                            // 抛出异常便于上层servlet捕获
                            throw e;
                        }
                        return result;
                    }
                });
    }

    /**
     * 使用cglib动态代理生成代理对象
     * @param obj 委托对象
     * @return 代理对象
     */
    public Object getCglibProxy(Object obj) {
        return Enhancer.create(obj.getClass(), new MethodInterceptor() {
            @Override
            public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
                Transactional transactional = method.getAnnotation(Transactional.class);
                if (transactional == null) {
                    return method.invoke(obj, objects);
                }
                Object result = null;
                try{
                    // 开启事务(关闭事务的自动提交)
                    transactionManager.beginTransaction();
                    result = method.invoke(obj, objects);
                    // 提交事务
                    transactionManager.commit();
                }catch (Exception e) {
                    e.printStackTrace();
                    // 回滚事务
                    transactionManager.rollback();
                    // 抛出异常便于上层servlet捕获
                    throw e;
                }
                return result;
            }
        });
    }
}
